Hydrorefining of crude oil and catalyst therefor



United States Patent 3,173,860 HYDROREFINING 53F CRUDE OIL AND CATALYSTT EiEREFQR John G. Gatsis, Chicago, BL, assignor to Universal GilProducts Company, Des Plaines, EL, a corporation of Delaware N0 Brawirw.Filed Dec. 2%, 1961, Ser. No. 10fi2 9 Claims. (Cl. 208-264) The presentinvention relates to a novel, method for preparing a catalystparticularly adaptable for utilization in the hydro-refining ofpetroleum crude oils, heavy vacuum gas oils, heavy cycle stocks, etc.More specifically, the present invention involves a process for thehydrorefining of heavy hydrocarbon charge stocks to effect the removalof nitrogen and sulfur therefrom, and aitords unexpected advantages whenemployed for the removal of metals and/or to convert thepentane-insoluble fraction thereof into useful pentane-solublehydrocarbon oils.

Crude petroleum oil, and the heavier hydrocarbon fractions and/ ordistiliates obtained therefrom, generally contain nitrogenous andsulfurous compounds in large quantities. In addition, crude oil andheavier hydrocarbon fractions contain quantities of metalliccontaminants which exert detrimental effects upon the catalyst utilizedin various processes to which the crude oil or heavy hydrocarbonfraction is ultimately subjected. The most common metallic contaminantare nickel and vanadium, although other metals including iron, copper,etc., are often present. These metals may occur in a variety of forms:they may exist as metal oxides or as sulfides, introduced into the crudeoil as metallic scale or particles; in the form of soluble salts of suchmetals; usually, how ever, they exist in the form of organo-metalliccompounds such as metal porphyrins and the derivatives thereof.

Although the metallic contaminants existing as oxide or sulfide scalemay be removed, at least in part, by a relatively simple filteringtechnique, and the water-soluble salts are at least in part removable bywashing and subsequent dehydration, a much more severe treatment isgenerally required to remove the organo-metallic compounds, and to thedegree required in order that the resulting crude oil or heavyhydrocarbon fraction is suitable for further processing. In addition tothe organernetallic compounds, including metal porphyrins, crude oilscontain greater quantities of sulfurous and nitrogenous compounds thanare found in li hter hydrocarbon fractions such as gasoline, kerosene,light gas oil, etc. For example, a Wyoming sour crude, having a gravityof 23.2" API at 60 F., contains about 2.8% by weight of sulfur and about2700 ppm. of total nitrogen. The nitrogenous and sulfurous compounds areconverted, up on being subjected to a treating process, intohydrocarbons, ammonia, and hydrogen sulfide, the latter being readilyremoved from the system in a gaseous phase. Reduction in theconcentration of the metallic contaminants is not as easily achieved,and to the extent that the crude oil or heavy hydrocarbon charge stockbecomes suitable for further processing. Notwithstanding that theconcentration of these compounds, such as metal porphyrins, isrelatively small, for example, less than about 10 p.p.m., calculated asthe elemental metal, subsequent processing techniques will be adverselyaifccted thereby. For example, when a hydrocarbon charge stockcontaining metals in excess of about 3.0 p.p.m., is subjected to acracking process for the purpose of producing lowerboiling components,the metals become deposited upon the catalyst employed, steadilyincreasing in quantity until such time as the composition of thecatalytic composite is changed to the extent that undesirable resultsare obtained. That is to say, the composition of the catalyticcomposite, which is closely controlled with respect to the "ice natureof the charge stool; being processed and to the desired product qualityand quantity, is changed considerably as the result of the deposition ofthe metallic contaminants onto the catalyst, the changed compositeresulting in changed catalytic characteristics. Such an effect isundesirable with respect to the cracking process, since the depositionof metallic contaminants upon the catalyst tends to result in a lesserquantity of valuable liquid product, and large amounts of hydrogen andcoke, the latter producing relatively rapid catalyst deactivation. Thepresence of organic metal compounds, including metal porphyrins, affectsdeleteriously other processes including catalytic reforming,isomerization, hydrodeallrylation, etc.

In addition to the foregoing described contaminating influences, crudeoils and other heavier hydrocarbon fractions, generally contain largequantities of pentane-insoluble material. For example, the Wyoming sourcrude consists of about 8.37% by weight of pentane-insoluble asphalteneswhich are hydrocarbonaceous compounds considered as coke-precursorshaving the tendency to become immediately deposited within the reactionzone and onto the catalytic composite employed in the form of a gummyhydrocarbonaceous residue. This constitutes a large loss of chargestock; it is economically desirable to convert such asphaltcnes intouseful hydrocarbon oil fractions.

The object of the present invention is to provide a much more efficientprocess for hydrorefining heavier hydrocarbonaceous material, andparticularly petroleum crude oils, utilizing a catalyst prepared in aparticular manner. As above set forth, metals are generally removed fromthe charge stock by deposition of the same on the catalyst employed.This greatly increases the amount of catalyst in a very short time, andprecludes the use of a fixed-bed catalyst system as employed inpracticing present-day methods. Slurry processes, employingcatalytically active metals deposited upon silica and/or alumina, areextremely erosive, and make plant maintenance ditficult and expensive.The present invention teaches the preparation of a collodiallydispersed, unsupported catalyst useful in a slurry process, and whichwill not effect extensive erosion of the reaction system. The presentprocess yields a liquid hydrocarbon product which is more suitable forfurther processing without experiencing the difiiculties otherwiseresulting from the presence of the foregoing contaminants. The processof the present invention is particularly advantageous in eifecting theremoval of the organic metal compounds without significant product yieldloss, while simultaneously converting pentane-insoluble material intopentane-soluble liquid hydrocarbons.

In a broad embodiment, the present invention relates ,to a hydrorefim'ngcatalyst which comprises at least one decomposed organza-metalliccompound of the metals of Group VI-B, having an atomic number greaterthan 24, and the Iron-group.

Another broad embodiment of the present invention involves a method ofpreparing a hydrorefining catalyst which comprises forming a hydrocarbonsolution of at least one organo-metallic compound of the metals of GroupVI-B, having an atomic number greater than 24, and the Iron-group, landdecomposing said organo-metallic compound in said hydrocarbon.

A more limited embodiment of the present invention affords a process forhydroreiining a hydrocarbon charge stock which comprises admixing saidcharge stock with at least one organo-metallic compound of the metals ofGroup VI-B, having an atomic number greater than 24,

and the Iron-group, heating the resulting mixture at a temperature lessthan about 310 C. and for a time sufiicient to decompose saidorgano-metallic compound, reacting the resulting colloidal suspensionwith hydrogen at a temperature in excess of about 225 C. and at apressure of carbon monoxide, at a temperature within the range of fromabout 225 C. to about 500 C. and at a pressure of from about 500 toabout 5000 pounds per square inch gauge, and recovering said crude oilsubstantially free from pentane-insoluble asphaltenes.

From the foregoing embodiments, it is readily ascertained that themethod of the present invention involves the preparation of a catalystutilizing metals selected from Group VI-B and the Iron-group of thePeriodic Table. The catalyst, prepared in accordance with the method ofthe present invention, may comprise one or more metals from the group ofmolybdenum, tungsten, iron, nickel and cob-alt. It is noted that themetal selected from Group VI-B, namely molybdenum and/or tungsten, hasan atomic number greater than 24. I have found that organic chromiumcomplexes, upon decomposition, do not yield acceptable results,particularly with respect to the conversion of the pentane-insolublematerial, and the destructive removal of the organo-metals such asnickel and/ or vanadium porphyrins. The catalyst is prepared byinitially dissolving an organic complex of the selected metal, ormetals, in the hydrocarbon charge stock containing the pentane-insolublefraction which is to be converted into soluble hydrocarbons. Thequantity of the organo-metallic compound employed is such that thecolloidal suspension, or dispersion, which results when theorgano-metallic compound is decomposed within the hydrocarbon chargestock, comprises from about 1.0% to about 10.0% by weight, calculated asthe elemental metal. Suitable oragno-metallic compounds includemolybdenum hexacarbonyl, tungsten hexacarbonyl, iron pentacarbonyl,

molybdenum hexacarbonyl in combination with nickel formate, tungstenhexacarbonyl in combination with iron carbonyl, various cobaltcomplexes, etc.

The process is effected, as hereinabove set forth, by initiallydissolving the desired quantity of the organometallic compound, such asmolybdenum hexacarbonyl, in the hydrocarbon charge stock. The resultingmixture is then heated, preferably in a non-reducing atmosphere,

particularly in the absence of free hydrogen, at a tempera ture lessthan about 310 C. and for a time sufficient to effect the decompositionof the organo-metallic compound, thereby resulting in a colloidalsuspension, or dispersion, of the metallic component Within thehydrocarbon charge stock. As hereinafter set forth, the presence of freehydrogen during the decomposition of the organometallic compound has atendency to affect detrimentally the activity of the catalyst withrespect to the conversion of the pentane-insoluble fraction as well asthe removal of metals. The colloidal dispersion is then passed into asuitable reaction zone at a temperature within the range of from about225 C. to about 500 C. under a hydrogen pressure within the range ofabout 500 to about 5000 pounds per square inch gauge. In order tomaintain the catalyst in its decomposed form, either as the metal or asa lower oxide thereof, it is necessary that the reaction zone bemaintained substantially completely free from carbon monoxide. Followingthe decomposition of the molybdenum hexacarbonyl, some carbon monoxidewill be present in the gaseous phase. This is readily removed uponventing prior to passing the mixture into the reaction zone. Where someof the carbon monoxide is dissolved in the liquid phase, it is preferredto remove the same by suitable stripping means. The process may beconducted in a batch-type procedure or in an enclosed vessel throughwhich the colloidal suspension is passed; when efiected in a continuousmanner, the process may be conducted in either upward flow or downflow.The normally liquid hydrocarbons are separated from the total reactionzone effiuentby'any suitable means, for example, through the use of acentrifuge, the resulting catalyst sludge being converted back to theoragno-metallic compound by any well-known'chemical means. The ammoniaand hydrogen sulfide, resulting from the destructive conversion ofsulfurous and nitrogenous compounds contained within the hydrocarboncharge stock, are removed, along with any light paraffinic hydrocarbonsincluding methane, ethane and propane, in a gaseous phase.

Although the process of the present invention is conducted in thepresence of hydrogen, the decomposition of the organo-metallic compound,such as molybdenum hexacarbonyl, is effected in the absence thereof. Ifpresent, hydrogen will react with the carbon monoxide, resulting in theformation of water, methane and carbon. It is further preferred that thedecomposition to form the colloidal suspension be conducted insubstantial absence of other well-known reducing agents. Depending uponthe particular organo-metallic compound selected at the catalyst source,the dispersed material will be the elemental metal or a lower oxide formthereof. In any event, it is understood that the stated concentrationsare computed on the basis of the elemental metal. The decomposiion ofthe oragno-metallic compound is conducted at a temperature less thanabout 310 C. in order to avoid initial cracking of the petroleum crudeoil prior to effecting complete decomposition.

The following example is given to illustrate the process of the presentinvention and the effectiveness thereof in removing nickel and vanadiumfrom the petroleum crude oil, and in converting pentane-insolubleasphaltenes while simultaneously effecting the conversion of sulfurousand nitrogenous compounds into sulfur and nitrogen-free hy= drocarbons.It is not intended that the present invention be unduly limited to thecatalyst, charge stock, and/or operating conditions employed within theexample. Spectrographic emission was employed to analyze the producteffluent for the concentration of metals remaining.

Example The crude oil employed to illustrate the benefits affordedthrough the utilization of the present invention, was a Wyoming sourcrude oil having a gravity of 232 API at 60 F, and containing 2.8% byweight of sulfur, approximately 2700 ppm. of nitrogen, 18 ppm. of nickeland 71 ppm. of vanadium as metal porphyrins, computed as the elementalmetal. In addition, the sour crude consisted of 8.37% by weight ofpentane-insoluble asphaltenes. As hereinafter indicated, the process ofthe present invention efiects the conversion of a significant proportionof such asphaltenes, and to the degree that the same no longer exert adetrimental effect upon further processing. I

The colloidally dispersed catalysts were prepared by decomposing theindicated organo-metallic compounds within the sour crude oil,thereafter subjecting the mixture to conversion in a rotating autoclavemaintained at about 400 C., at an imposed hydrogen pressure of about 200atmospheres. Each of the colloidal suspensions remained in the autoclaveat the foregoing conditions for a period of from about 4 to about 8hours.

Molybdenum hexacarbonyl, in an amount of 23.3 grams was admixed with 200grams of the Wyoming sour crude, the mixture being charged to therotating autoclave and heated to a temperature of 250 C. for a period of3 hours. After venting to remove carbon monoxide, the autoclave waspressured to atmospheres with hydrogen, and then heated to a temperatureof 400 C. for a period of about 8 hours, the final pressure being about200 atmospheres. The gravity, API at 60 F., of the resulting normallyliquid product effluent was 40.], indicating a substantial degree ofconversion to lower-boiling hydrocarbon products. The liquid productindicated only 7.1 ppm. of nitrogen, about 0.02% by weight of sulfur,about 0.10% by weight of pentane-insoluble asphaltenes, less than about0.02 ppm. of nickel and less than about 0.02 ppm. of vanadium.

When utilizing 23.3 grams of molybdenum hexacarbonyl, decomposed insitu, in the presence of hydro gen, the final liquid product was foundto contain 347 -p.p.m. of nitrogen compared to 7.1 ppm. of nitrogen ashereinabove set forth.

A mixture of 23.3 grams of molybdenum hexacarbonyl, 2.5 grams of nickelformats and 200 grams of the Wyoming sour crude, initially heated to atemperature of 250 C. for a period of 4 hours, was placed in therotating autoclave under a pressure of 100 atmospheres of hydrogen; uponbeing heated to a temperature of 400 C., the pressure increased to alevel of about 200 atmospheres. These conditions were maintained for aperiod of 8 hours, and the resulting normally liquid product etlluentindicated 124 p.p.m. of nitrogen, 0.02% by weight of sulfur, less than0.1% by weight of pentane-insoluble asphaltenes, less than 0.04 ppm. ofnickel and less than 0.04 ppm. of Vanadium.

The foregoing specification and example clearly illustrate theadvantages afiorded the hydroreiining of petroleum crude oils throughthe utilization of the method of the present invention. It is ofparticular interest to note that the concentration of nickel andvanadium, existing as organo-metallic complexes, as well aspentane-insoluble asphaltenes, was decreased to a level permittingsubsequent utilization of the crude oil, either for further processingor distillation, and further that at least a portion of the crude oilwas converted into lower-boiling hydrocarbon products.

I claim as my invention:

1. A process for hydrorefining a hydrocarbon charge stock whichcomprises admixing said charge stock with at least one organo-metalliccompound selected from the group consisting of hexacarbonyls andpentacarbonyls of molybdenum, tungsten, iron, nickel and cobalt, heatingthe resulting mixture in a non-reducing atmosphere at a temperature lessthan about 310 C. and for a time sufficient to decompose saidorgano-metallic compound, thereafter adding hydrogen to the resultingcolloidal suspension and reacting the mixture thus formed at atemperature in excess of about 225 C. and at a pressure greater thanabout 500 pounds per square inch gauge, and recovering a hydrorefinedliquid product.

2. The process of claim 1 further characterized in that the mixture ofsaid charge stock and decomposed organemetallic compound is reacted withhydrogen at a temperature within the range of from about 225 C. to about500 C. and under a pressure of from about 500 pounds per square inchgauge.

3. The process of claim 1 further characterized in that saidorgano-metallic compound comprises molybdenum hexacarbonyl.

4. The process of claim 1 further characterized in that saidorgano-metallic compound is a hexacarbonyl.

5. A process for hydrorefining a petroleum crude oil containingpentane-insoluble asphaltenes, which comprises admixing said crude oilwith at least one organo-metallic compound selected from the groupconsisting of hexacarbonyls and pentacarbonyls of molybdenum, tungsten,iron, nickel and cobalt, heating the resulting mixture in a non-reducingatmosphere at a temperature less than about 310 C. for a time sufficientto decompose said organometallic compound, thereafter adding hydrogen tothe resulting colloidal suspension and reacting the mixture thus formedat a temperature in excess of about 225 C. and at a pressure greaterthan about 500 pounds per square inch gauge, and recovering said crudeoil substantially free from pentane-insoluble asphaltenes.

6. The process of claim 5 further characterized in that the suspensionof said crude oil and decomposed organometallic compound is reacted withhydrogen in the sub stantial absence of carbon monoxide.

7. The process of claim 5 further characterized in that saidorgano-metallic compound comprises molybdenum hexacarbonyl.

8. The process of claim 5 further characterized in that saidorgano-metallic compound comprises molybdenum hexacarbonyl and nickelformate.

9. A process for hydrorefining a petroleum crude oil containingpentane-insoluble asphaltenes, which comprises admixing said crude oilwith molybdenum hexacarbonyl, heating the resulting mixture at atemperature less than about 310 C. in a non-reducing atmosphere and fora time suflicient to decompose said molybdenum hexacarbonyl, thereafteradding hydrogen to the resulting colloidal suspension and reacting themixture thus formed, in the substantial absence of carbon monoxide, at atemperature within the range of from about 225 C. to about 500 C. and ata pressure of from about 500 to about 500 pounds per square inch gauge,and recovering said crude oil substantially free from pentane-insolubleasphaltenes.

References Cited by the Examiner UNITED STATES PATENTS 2,781,410 2/57Ziegler et a1. 260-68315 2,999,075 9/61 Pruett 252-472 3,006,844 10/61Limido 208217 3,050,562 8/62 Klopfer 252-431 3,053,756 9/62 Nottes etal. 252431 5 ALPHONSO D. SULLIVAN, Primary Examiner.

PAUL M. COUGHLAN, 1a., Examiner.

1. A PROCESS FOR HYDROREFINING A HYDROCARBON CHARGE STOCK WHICHCOMPRISES ADMIXING SAID CHARGE STOCK WITH AT LEAST ONE ORGANO-METALLICCOMPOUND SELECTED FROM THE GROUP CONSISTING OF HEXACARBONYLS ANDPENTACARBONYLS OF MOLYBDENUM, TUNGSTEN, IRON, NICKEL AND COBALT, HEATINGTHE RESULTING MIXTURE IN A NON-REDUCING ATMOSPHERE AT A TEMPERATURE LESSTHAN ABOUT 310*C. AND FOR A TIME SUFFICIENT TO DECOMPOSE SAIDORGANO-METALLIC COMPOUND, THEREAFTER ADDING HYDROGEN TO THE RESULTINGCOLLOIDAL SUSPENSION AND REACTING THE MIXTURE THUS FORMED AT ATEMPERATURE IN EXCESS OF ABOUT 225*C. AND AT A PRESSURE GREATER THANABOUT 500 POUNDS PER SQUARE INCH GAUGE, AND RECOVERING A HYDROREFINEDLIQUID PRODUCT.